The present invention relates to a transparent conductive layer built-up material, and more particularly to a transparent conductive layer built-up material suitably usable, particularly, for electroluminescent display units.
Transparent conductive films or transparent conductive layer-built-up materials are extensively utilized in the electric or electronic field; for example, they are utilized as the electrode for liquid crystal display units, as the electrode for electroluminescent display units, as the electrode for photoconductive photoreceptors, for cathode-ray-tubes, as the static electricity-shield layer in the window section of various measuring instruments, as antistatic layers, as heating elements, and the like. Of these the transparent conductive film having selective light transmissibility, because of its infrared reflectibility, is applied as the collector window material for the untilization of solar energy and as the window material for buildings. Also, with the advance of information processing technology, various solid-state display units, as ones replacing the conventional Braun tubes, have been developed which use electroluminescent materials, liquid crystals, plasma, ferrodielectric substances, etc., and for these display units transparent electrodes are always used. Further, new electrooptical elements and recording materials which utilize the interaction or interconversion between electric signals and light signals are promising for the future information processing technology, and they also need the use of film having both transparency and conductivity. On the other hand, such transparent conductive film is also applicable as the antifogging window glass for motor vehicles, aircraft, etc.; as the antistatic layer for polymer or glass materials; and also as the transparent adiabatic window for preventing the scattering and loss of solar energy.
In recent years, particularly in liquid crystal display units, electroluminescent display units, plasma display units, electrochromatic display units, fluorescent display units, etc., needs of high-grade picture-element display have been raised, and to meet the needs there have been proposed the improvements on the displaying rate of the picture elements and on the display image quality through the formation of picture elements with an electrode comprising a transparent conductive layer and at the same time the formation of a signal application line with a low-resistance electrode comprising a metallic layer.
Conventional electroluminescent display units, however, have been found out to have the disadvantage of emitting uneven luminescent light during their operation because of the inadequately lowered resistance of the electrode and also because of the inadequate adhesive strength between the electroluminescent light emitting layer and transparent conductive layer when both layers are made adhere to each other by a method which will be described hereinafter.